1. Field of Invention
The present invention relates to a color loss determination printing method that enables easily determining loss of color ink in a color printer that prints in color using multiple colors of ink. The invention also relates to inventory management print media such as labels having a color loss determination area that is printed by the color loss determination printing method.
In the following specification, the term “ink” will be used for convenience. However, it is intended that “ink” shall be interpreted herein as a generic term that covers ink, toner, thermal print materials, or any other coloring agent that can be used to print in color. The terms “color ink” and “coloring agent” may be used interchangeably herein as generic terms that represent a liquid or material that can be used in color printing.
2. Description of Related Art
When products are distributed to and stored in multiple warehouses, an inventory management label on which are printed the product name and the name of the warehouse where the product will be stored is applied to the surface of the cardboard box in which the products are packaged. A color that is assigned to each warehouse name is also printed in an area of the inventory management label that is easy to read so that the person routing the products to the different warehouses can easily determine where to send each box.
If red (R) is assigned to warehouse A, blue (B) to warehouse B, yellow (Y) to warehouse C, and green (G) to warehouse D as shown in FIG. 4A, the inventory management labels that are used for storing roll paper in warehouse A, for example, are printed with red denoting warehouse A. In the sample inventory management label shown in FIG. 4B, the strips 70 at the top and bottom of the inventory management label are the identification color printing area where red is printed on the inventory management label.
An inventory management label with an identification color printing area is commonly printed using a color inkjet printer that prints using four colors of ink, black (K), cyan (C), magenta (M) and yellow (Y), for example. Such inkjet printers print the color assigned to each warehouse in the identification color printing area by overlaying different colors of ink in a known ratio in order to print a desired color.
If, when printing the inventory management labels with an inkjet printer the identification color printing area is printed without using one of the required colors because the supply of that color ran out, for example, the identification color printing area will be printed with a uniform color just as when the identification color printing area is printed normally but the resulting color will differ from the color that should be printed. This is referred to as “color loss.”
As shown in FIG. 4C, when the inventory management label shown in FIG. 4B is printed when magenta (M) is lost, the strips 70 of the inventory management label are printed yellow (Y). As shown in FIG. 5, the red (R) that is desired to be printed in the strips 70 is printed normally using magenta (M) and yellow (Y) inks (red is the complement of magenta and yellow). However, only yellow (Y) is printed if magenta (M) is lost, and the resulting label will be printed with yellow (Y) denoting warehouse C. As a result, the worker reading the inventory management label printed with color loss may very likely send the boxes containing roll paper to warehouse C instead of the correct warehouse A. The worker will not realize that the wrong color has been printed because the label will still look ok.
The same problem occurs when other colors of ink are lost. Referring to FIG. 5, blue (B) is printed normally using cyan (C) and magenta (M) inks (blue is the complement of cyan and magenta). Therefore. only magenta (M) ink will be printed if cyan (C) is lost, and the color printed in the identification color printing area will be magenta (M), which can easily be mistaken for red (R).
Likewise, green (G) is printed normally using cyan (C) and yellow (Y) inks (green is the complement of cyan and yellow). Therefore, only cyan (C) ink will be printed if yellow (Y) is lost, and the color printed in the identification color printing area will be cyan (C), which can easily be mistaken for blue (B).
Japanese Unexamined Patent Appl. Pub. JP-A-H09-66650, for example, teaches a method of confirming whether each color of ink is discharged normally from the ink nozzles of the inkjet head by printing a test pattern. However, even if a test pattern is printed and it is confirmed that there is no color loss at the start of printing, this method cannot determine if color loss suddenly occurs while printing is in progress.
It is also conceivable to limit the colors printed in the identification color printing area to the four primary ink colors. If only the primary colors are then printed, the base color of the inventory management label will appear in the identification color printing area if one of the colors is lost, and color loss can be easily confirmed. This does not allow management using more than four colors, however, and is therefore not practical.
It is also conceivable to print a color sample 75 having four printing areas each printed with one of the colors black (K), cyan (C), magenta (M), and yellow (Y) as shown in FIG. 6 in a prescribed area of the management label so that color loss can be determined from this color sample 75. Color loss can be confirmed if any one of the four printing areas is not printed in the color sample 75.
However, looking at a color sample 75 having four small printing areas and confirming whether each of the printing areas is correctly printed is bothersome and time-consuming. In addition, the area printed with yellow (Y) ink can be difficult to discern because of the small area, and confirming color loss is not easy. A problem with the color loss determination printing method that prints such a color sample 75 is that it is difficult to readily and accurately evaluate color loss.